(a) Field of the Invention
The present invention relates to an electron emission device and a method of manufacturing the same. More particularly, the present invention relates to an electron emission device and a method of manufacturing the same that embody a high current density and a high electron emission degree by adjusting average surface roughness.
(b) Description of the Related Art
Due to excellent electric characteristics, mechanical characteristics, and chemical characteristics of a carbon nano tube, in a field of an X-ray tube, a fluorescent tube, and a flat plate display, the carbon nano tube is widely used as an electron emission source. Conventionally, an X-ray tube using a thermal electron emission source such as a tungsten filament has been widely used, but a much production cost is required, operation is performed in a high temperature condition, and power consumption is large. Particularly, because upon applying as a micro focusing X-ray electron source, it is difficult to form the X-ray tube in a small size and the X-ray tube is less used due to a short life-span.
As a general electron emission source, a structure that forms a buffer layer in a metal tip that is formed with tungsten and that forms a catalyst material and that grows a carbon nano tube is much used. In such a structure, because of multi-layered structural characteristics, the structure has large contact resistance, thereby the large contact resistance becomes a cause that reduces a voltage supply for electron emission and therefore when the X-ray tube operates in a high pressure for a long time, a much heat occurs and adhesion is thus deteriorated. Therefore, important characteristics of a threshold voltage, a maximum emission current, reliability, and a life-span are deteriorated.